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Procedia CIRP 12 (2013) 348 – 353
8th CIRP Conference on Intelligent Computation in Manufacturing Engineering
Software tool for planning and analyzing engineering changes in
manufacturing systems
R.C. Malaka,*, J.C. Auricha
a
Institute for Manufacturing Technology and Production Systems, University of Kaiserslautern, P.O. Box 3049, 67653 Kaiserslautern, Germany
* Corresponding author. Tel.: +49-631-205-4282; fax: +49-631-205-3304. E-mail address: malak@cpk.uni-kl.de.
Abstract
Companies are facing an increasing number of engineering changes (ECs) in manufacturing systems (MS). The planning of ECs
becomes a continuous task. It has to be proceeded properly in order to identify the efforts of the implementation and to reduce the
risk of production shutdowns. Tools of the digital factory are able to support the planning and analyzing procedure.
In order to improve the handling of ECs, an approach for planning and analyzing is presented. It starts with a systematic description
of ECs. This systematic description initiates modules to analyze the impacts on MS and to automatically generate plans for the
implementation. The planning and analyzing procedure is implemented in a software demonstrator which enables an intuitive
navigation for the planning engineer. This software demonstrator provides direct feedback based on planned ECs. Its functionality
is demonstrated and validated by a use case.
© 2013 The Authors. Published by Elsevier B.V. Open access under CC BY-NC-ND license.
© 2012 The Authors. Published by Elsevier B.V. Selection and/or peer-review under responsibility of Professor Roberto Teti.
Selection and peer review under responsibility of Professor Roberto Teti
Keywords: Planning; Digital Factory.
1. Introduction
Companies need to continuously adapt their
manufacturing systems (MS) to keep up with shorter
innovation cycles, competition, and a rapidly changing
market. According to that, companies have to implement
numerous engineering changes (ECs): This development
requires a systematic and fast method for planning and
analyzing ECs [1]. Inaccurate planning and analyzing of
ECs lead to production shutdowns, time delays, and
consequently cause high costs [2]. In addition to caused
production shutdowns, ECs have to be re-planned and
analyzed. This leads to postponed deadlines and cause
high cost [3, 4].
The increasing number of ECs and the reduced
available time for planning and analyzing them causes a
dilemma (Figure 1). On the one hand, this leads to a
decreasing quality in planning and analyzing, which in
turn leads to the necessity of re-planning or to
ineffective ECs. Financial restrictions and time pressure
prevent a detailed analysis [5]. On the other hand, the
reduced available planning time leads to a reduced
implementation of ECs. This leads to an increasing stock
of required ECs.
Possible solutions
Additional resources
Decreasing
quality
of planning
and analyzing
Increased efficiency
Less time
for planning
Less ECs are
implemented
Increasing
number of ECs
Replanning
and/or
ECs are not
effective
Decreasing
productivity
Increasing
of ECs
Dilemma of ECs
Fig. 1. Dilemma of ECs
The decreased planning and analysis quality, as well
as less implemented ECs, are reducing the productivity.
This leads to further required adaptations in MS. There
are two possibilities to solve that dilemma: additional
2212-8271 © 2013 The Authors. Published by Elsevier B.V. Open access under CC BY-NC-ND license.
Selection and peer review under responsibility of Professor Roberto Teti
doi:10.1016/j.procir.2013.09.060
R.C. Malak and J.C. Aurich / Procedia CIRP 12 (2013) 348 – 353
planning and analyzing resources and an increased
planning and analyzing efficiency. Additional planning
and analyzing resources can be established, for example,
through new personnel or external services. The
efficiency of planning and analyzing can be increased
through supporting software tools. They are able to
accelerate the planning and analyzing procedure and
enable a high quality. For this reason, software tools are
required which support planning and analyzing ECs in
MS by accelerating the procedure.
In this paper, we present a conceptual work for a
software tool that supports planning, analyzing, and the
implementation of ECs in MS. We implement this
approach in a software demonstrator, programmed with
JAVA 3D, and illustrate its application in a case study.
2. .State of the art
2.1. ECs in MS
The term EC originates from the area of product
development. Additionally, ECs occur in MS and can be
described as follows [6, 7]:
reconfiguration of production objects, as for example
machines and working places;
addition, substitution, and removal of production
objects, e.g. machines or tools;
changes to the structure of interrelationships between
production objects.
MS can be separated into the levels network,
production site, system or segment, machine, as well as
processes and tools [8]. ECs do not concern whole
production sites or networks. They are related to the
segment or system level (part production, machining,
assembly, etc.)with machines and workplaces as
subsystems. Compared to factory planning, ECs are not
necessarily related to investment decisions. They are
usually on the level of machines and workplaces. The
system boundary is a manufacturing segment and
within departments or segments independently from
other departments or levels.
2.2. Planning and analyzing ECs in MS
Depending on the described level, there are different
approaches for planning and analyzing ECs in MS.
Factory planning concerns the level of production sites
and networks. The procedure is divided into different
phases which are supported by methods and tools [3]. It
is not suitable for ECs for the following reasons:
continuous need for ECs,
consideration of the running production,
consideration of restrictions of the current production
environment,
349
partially small investment,
partially less effort of implementation,
etc.
Approaches for planning and analyzing ECs are the
continuous improvement process (CIP) [9], process
optimization
[10],
and
reengineering
[11].
Reengineering is the analysis of existing processes with
the scope of dramatic improvements in critical,
contemporary measures of performance [11]. Roessing
presents an approach for combining ECs in
manufacturing systems and processing them as EC
projects [12].
2.3. Support by tools of the digital factory
The planning and analyzing procedure of ECs in MS
can be supported by tools of the digital factory [13]. The
digital factory is defined as a set of computer aided
methods and tools to provide a virtual production model.
They can be used for planning, experimenting and
implementation [14]. Tools of the digital factory have
the potential to support the planning and analysis of ECs
in MS and accelerate the procedure. These software
tools can be classified into [15]:
modeling and visualization,
simulation and evaluation, and
data management and communication.
Modeling and visualization software is applied to
rebuild and represent MS. Simulation and evaluation
software is applied in order to analyze processes or
object behaviors. The different type of data is managed
and communicated by the third software category.
The idea of the digital factory is managing the usually
isolated and separated tools to a whole [16]. But this is
still a concept and unimplemented yet for many reasons.
Tools of the digital factory do not offer all required
functionalities and have a lack of interoperability [17].
Interfaces between the software tools are still required
and the transfer between the tools has to be done
manually [18]. Many interfaces and incompatibilities
foreclose a seamless integration [19]. Changes in a 3Dmodel with CAD-Software are not directly considered in
a material flow simulation for example.
However, it is not widespread yet, especially not in
small and medium-sized enterprises (SME) [20]. One
reason is the required software specific know-how [21].
It requires qualified personnel and training, which in
turn requires financial resources. Additionally, the
financial effort for acquiring these tools is very high,
especially for SMEs [22]. Another important issue is the
transfer of data and models into the tools and keeping
them up to date [22]. These aspects have to be
considered for the development of software tools.
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R.C. Malak and J.C. Aurich / Procedia CIRP 12 (2013) 348 – 353
3. Planning and analyzing algorithm for ECs
The planning and analyzing algorithm (figure 2)
contains three main procedures: description of ECs,
analysis, and EC implementation planning. The EC
description is the initial part of the algorithm and
described in detail in chapter 3.1. It is the basis for the
analysis in chapter 3.2. EC implementation planning
starts after the analysis in chapter 3.3. The algorithm
ends with the implementation of ECs.
EC description
Adaption
Analysis
Layout
process chains are evaluated based on estimated
production times (machining, transport, buffer, and
handling). The impacts are identified through comparing
the planned with the current cycle times of the process
chain. Then, conflicts between machines are derived.
Therefore, conflict initiating (for example heat emissions
through ovens or vibrations through forming machines,
etc.) and conflict affecting attributes (for example
vibration for micro machines) are described for each
machine. ECs have impact on interrelationships in MS
and can interrupt them. This leads to production
shutdown. All processes for each product have to be
defined after an EC.
3.3. EC implementation planning
Process chain
Conflicts
Interrelationships
yes
Planning EC
implementation
Result
o.k.?
no
Result
o.k.?
no
yes
EC implementation
Fig. 2. EC planning and analyzing algorithm
Based on the aforementioned basic operations and the
machines, the implementation has to be planned.
Therefore, tasks for the implementation are described in
a solution database by two parts (figure 3): one part
contains information for allocating the tasks and the
other one for describing them. Information for allocating
the tasks is: basic operations, phases, and machine
classes. The machine classes are described by the
relevant attributes and the considered boundaries. The
tasks are specified by a description of the tasks, required
resources, time, cost, risks, counter measures, etc.
3.1. Description of ECs
The systematic description of ECs through defined
characteristics is the basis for the analysis and the
planning of the implementation. Therefore, the
description is significant for the following steps.
For the systematic description, ECs are separated into
several procedures named basic operations. With these
basic operations ECs are described together with the
involved machines. The basic operations for ECs are:
addition, removal, and transport of machines as well as
addition and removal of processes. The description of
ECs consists of these basic operations together with
relevant information considering the basic operations
and machines (for example required area and position
for adding a new machine).
Description
Machine
EC
Projectplan
Basic operation (BO)
Implementation tasks
BO
Phase
Class
Task
BO 1
BO 1
BO 1
BO 1
BO 2
Prepare
Prepare
Process
Post
Prepare
A
B
A
A
C
Task 1
Task 2
Task 3
Task 4
Task 5
BO n
Prepare
Z
Task p
Criteria for allocation
Task
Task 1
Task 3
Task 4
Task 12
Time/
Cost
h/
h/
h/
h/
h/
...
h/
Information.
Doc 1
Link 2
Doc 12
Resource
Res. 2
Res. 1
Res. 3
Res. 1
Res. 1
Res. 3
Task description
Implementation plan
Time/Cost
h/
h/
h/
h/
Time
3.2. Analysis
Fig. 3. EC implementation planning
The analysis is separated into layout, process chains,
conflicts, and interrelationships. The layout analysis
considers, whether the requirements of the ECs are
feasible in the layout. The requirements are classified
into: fixtures, supply systems (pressurized air, water,
electricity, chip conveyor, etc.), dimension (machine,
workplace, buffer, etc.), load capacity of the floor, and
special requirements (constant temperature, acid
resistant floor, etc.). Additionally, the impacts on
As depicted in the figure, the implementation plan is
derived from the implementation tasks. The storage of
implementation tasks enables the collection and the
reuse of experiences, gained through former ECs. A
continuous improvement by managing the task
descriptions provides a learning procedure.
The functions of the approach are implemented in a
software demonstrator in order to provide the planning
and analyzing procedure for ECs in MS.
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R.C. Malak and J.C. Aurich / Procedia CIRP 12 (2013) 348 – 353
4. Software implementation
A: Menu
The presented approach is implemented in a software
demonstrator. The software demonstrator is programmed
with Java 3D. Java 3D is able to process many data
formats and is web ready. The software demonstrator is
separated into three layers: user, kernel, and data base
(figure 4).
User
Kernel
Database
Graphical user interface (GUI)
Data of
the MS
Data management
3D objects
MS data
Implementation
tasks
Fig. 4. Software architecture
The user navigates and applies the software through a
graphical user interface (GUI). The kernel contains the
3D environment of the MS and the corresponding data.
The planning and analyzing algorithms are connected to
the data management of the database. The database
contains 3D objects, MS data, and implementation tasks.
3D objects are stored as OBJ files. The MS database and
the solution database consist of CSV files.
4.1. Application of the software demonstrator
User
The application of the software demonstrator is
illustrated in figure 5. The user describes ECs. The
description of ECs initiates the planning algorithm,
which changes the 3D objects and the data of the MS.
Plan for
implementation
EC
Database
Kernel
Analysis results
Planningalgorithm
changes
choses
Analysisalgorithm
Manufacturing- and
object database
Solution database
D.
C: MS data
B.
Fig. 6. Graphical user interface (GUI)
Planning and
analyzing
algorithm
g
3D MS
environment
C.
B: 3D environment
D: Evaluation
Desktop
A.
Changed data
chosen tasks
Fig. 5. Software application
The changed data is processed by the analyzing
algorithms and the results are illustrated to the user.
After deciding to implement the EC, planning algorithms
chose the relevant implementation tasks out of the
solution database and illustrate them to the user. The
GUI is illustrated in figure 6.
The GUI is separated into the areas A to D:
A is the program menu. Therein, the user can manage
projects, change views, navigate, plan ECs, and view
the process chain.
B is the 3D environment.
C illustrates data of machines, buildings, and
interrelationships.
D is the evaluation area. Therein, the results of EC
analysis are illustrated.
4.1.1. Description of ECs
The user describes ECs over the GUI. Its activities
are used by the planning and analyzing algorithms. It is
possible to remove, add, or move machines in the 3D
environment. Movements are executed with keyboard
controls. Interrelationships between machines and
products can be added and removed. If interrelationships
are added, the user will be automatically asked for
production times of the concerned processes. Through
the described changes, the related data is also changed.
Adding or removing objects means that objects are
removed from the 3D environment or added from a
library with 3D objects. The corresponding data of the
objects are also added and removed. Removing an object
induces a removal of all interrelationships between that
object and the related products. A transport of an object
in the 3D environment leads to a position change, which
will be stored in the MS database. Removing and adding
interrelationships, creates new or removes existing
processes. The software demonstrator asks automatically
for estimated production times, when generating new
processes.
4.1.2. Analysis
Based on their description, ECs are analyzed
considering the layout, the process chain, conflicts, and
interrelationships. The aforementioned aspects in chapter
3.2 are analyzed and visualized in the software
demonstrator. The impacts of ECs are immediately
illustrated in the 3D environment and in the evaluation
area.
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4.1.3. Plan for EC implementation
Based on the description of ECs, the implementation
is planned with the software. Figure 7 shows how an
implementation plan is derived from the activities of a
user.
MS tn
EC
Basic operation:
Transport
Machine:
CNC turning i
Turning
Grinding
Grinding 2
MS tn+1
Balancing
Washing
Fig. 8. Manufacturing process of turbine wheel with shaft
Attribut 1
Attribut 2
Database with
implementation
p
tasks
Welding
Implementation plan
Fig. 7. EC implementation planning
The basic operations and the machines involved in
the EC determine the required implementation tasks of
the solution database. An implementation plan outlines
all tasks that are necessary to implement ECs. With
additional information like required resources, time,
cost, risks, measures, etc. the user is supported. The
implementation tasks of the solution database are easily
managed through standard forms without any special
software specific know-how. Deviations between the
plan and the implementation can be stored in the
solution database and are available in the future.
Additionally, reasons and counter measures for time
delays or budget overrunning are stored in the solution
database and are automatically considered for future
planning.
5. Use case
5.1. Initial situation
The use case originates from an industrial partner of
the Institute of Manufacturing Technology and
Production Systems. It is a manufacturer of exhaust
treatment systems which has to reorganize its
turbocharger production in order to manufacture
increasing production volumes and to increase
productivity. The considered area is the manufacturing
of turbine wheels and shafts (figure 8). The turbine
wheel is purchased and welded with a shaft. After that,
the shaft is manufactured with turning, and two grinding
processes. Then, the component is balanced and washed.
The production is organized workshop oriented and
partially contains older machines. The material flow is
unstructured and contains many buffers and
consequently high stocks.
In order to reorganize the production, following
issues have to be proceeded:
reorganizing the workshop oriented production to
eight product oriented manufacturing lines,
purchasing of new machines,
stock reduction and decreasing the throughput time,
Implementing the ECs within the running production
is quite challenging. The restrictions of the facilities, the
production equipment, and the running production have
to be considered. The implementation of the
manufacturing lines is proceeded iteratively in order to
better plan the ECs. This gives the opportunity to learn
from the ECs and to improve the planning and
implementation process. In order to manage the
reorganizing process and the required ECs the software
demonstrator is applied.
5.2. Application
The objects and the attributes of the new machines
are gathered from the machine suppliers and stored in
the library of the software demonstrator. Then
alternative ECs are described. The ECs are analyzed by
the software demonstrator considering the layout,
process chains, conflicts, and the interrelationships.
After choosing a solution, the required tasks are gathered
through a workshop. The identified tasks are stored in
the solution database and an implementation plan is
generated. The implementation plan is used to control
the EC implementation. Deviations and their reasons are
investigated. Then, countermeasures are identified and
documented in the software demonstrator together with
the risks for deviations. Consequently, the
implementation of the following ECs can be planned
more precisely and the risk of time delays and budget
overrun can be reduced.
5.3. Results
With the software demonstrator the required ECs for
reorganizing the MS can be planned with one software
tool. The required analysis ensure the feasibility of the
planned ECs and consequently avoid required
adjustments, and thus time delays and budget overrun.
R.C. Malak and J.C. Aurich / Procedia CIRP 12 (2013) 348 – 353
The automatic generation of implementation plans and
the easy improvement of the data base with
implementation tasks enable a reliable implementation
planning and provide experiences of former ECs for the
future.
6. Summary and outlook
In this paper, a software concept is presented which
supports the planning and analyzing procedure of ECs in
MS. The processes of describing, analyzing, and
planning the implementation of ECs is provided by one
software tool. The presented software demonstrator
manages data from different databases, is easy
applicable, and accelerates the planning and analyzing
procedure.
In order to improve the software demonstrator and to
increase the applicability in practice, there are still some
issues to research. Initially, a concept is required to
embed the software in existing IT infrastructure of
companies. Therefore, the current IT infrastructure of
companies has to be investigated and interfaces have to
be defined. In order to enable a centralized planning and
analyzing of ECs for production sites in other locations,
a web based software tool is recommended. Therefore
questions of data security and rights of intellectual
property have to be investigated.
Acknowledgements
The research described in this paper results from a
project funded by the German Research Foundation
-1).
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